This invention relates to an improved brass alloy and its fabrication process, and in particular to a ternary brass alloy which may be fabricated into strip, sheet, or wire and which has a low spring back coefficient and a shape memory effect.
Utilization of various alloying elements in a brass (copper-zinc) system has been suggested heretofore for the purpose of obtaining certain desired characteristics in the system. Edmunds in U.S. Pat. No. 2,394,673, for example, suggested the addition of 1.2% silicon to a 70/30 cartridge brass to provide a resistance to season cracking. One of the present inventors has investigated numerous ternary beta brass alloys and has reported his findings in the Transactions of the Metallurgical Society of AIME, Volume 230 (1964), Page 267; Volume 230, Page 1662 (1964); Volume 236, Page 1532 (1966); Volume 239, Page 756; Volume 239, Page 1668 (1967); and Metallurgical Transactions, Volume 1, Page 251 (1970).
These cited references report studies relating to the Martensitic transformations of various ternary brass alloys. A determination was made of the Martensitic transformation temperature as a function of the percentage of the third element content in such alloys. In addition, an investigation of the reaction of such alloys to stresses and temperature changes were reported in these various publications. These publications thus serve as a part of the background upon which a reservoir of knowledge has been developed by the present inventors. Subsequent developmental work to that reported in these various publications has resulted in the development of the presently claimed invention. This subsequent developmental work has resulted in the discovery of a copper-zinc-silicon ternary alloy and its fabrication process, one form of the alloy having an exceptionally low and unexpected spring back coefficient. In addition, another form of the alloy exhibits the so-called "super elastic" behaviour as well as the so-called "shape memory effect".